Your phone keeps a running count of the mobile data each line and app uses. Short answer: on iPhone, go to Settings → Cellular (or Mobile Data). On a Pixel, go to Settings → Network & internet → SIMs. On Samsung, go to Settings → Connections → Data usage → Mobile data usage.
The phone's figure is an estimate. Apple, Google and Samsung all say your carrier or eSIM provider may count usage differently, and the provider's figure is the one your plan runs on.
On iPhone
- 1Open Settings → Cellular (called Mobile Data in some regions).
- 2Near the top is the cellular data used for the current period: the time since the counter was last reset.
- 3Scroll down to the app list to see how much each app has used. Tap Show All if the list is shortened.
- 4Tap System Services to see data used by iOS itself. You can't switch cellular data off for individual system services.
Turn off data for one app: switch it off in the same list, and that app will only use Wi-Fi.
Reset the counter: scroll to the bottom and tap Reset Statistics. Do this when your trip, or a new plan, starts, so the figure matches that plan.
Use less in the background: turn on Low Data Mode under Settings → Cellular → Cellular Data Options. On 5G, it's under Data Mode; with two lines, tap the line first. It pauses automatic updates and background tasks while you're off Wi-Fi.
Using Dual SIM: the figures are for the line currently selected for cellular data. Apple says that for the most accurate figure for the current period, you should check with your carrier.
On Google Pixel
- 1Open Settings → Network & internet → SIMs and choose the SIM if you have more than one.
- 2Your total data use is shown at the top.
- 3Tap App data usage for a graph and a per-app list. Use the down arrow to change the time period.
Get a warning before you run out: go to SIMs → Data warning & limit, turn on Set data warning, then enter an amount in MB or GB.
Stop data at a set amount: turn on Set data limit. When you reach it, mobile data turns off until you switch the limit off again.
Some of these steps need Android 8.0 or later. Google also notes that your carrier may count usage differently from the phone.
On Samsung Galaxy
- 1Open Settings → Connections → Data usage.
- 2Tap Mobile data usage to see usage by app. Wi-Fi data usage is a separate list.
- 3To stop an app using data in the background, open it in the list and turn off Allow background data usage.
Match your plan's dates: in Mobile data usage, tap the gear icon, then Start billing cycle on. The same screen lets you set a data warning and a data limit.
Data saver: under Data usage → Data saver, turn on Turn on now to stop some apps using data in the background. You can still allow chosen apps.
Samsung notes that the mobile data screens aren't available without an active SIM, and that menus vary by carrier and model.
On other Android phones
Menu names differ by brand, but data usage almost always sits under Settings → Network & internet, Connections or Mobile network. Search Settings for "data usage" if you can't find it.
Why your phone and your provider show different numbers
- Different start dates. Your phone counts from its last reset, while your plan counts from activation or the start of your billing period.
- Different counting. Phone makers and carriers measure data in their own ways. All three say to treat the carrier's figure as the official one.
- Different lines. On a dual-SIM phone, make sure you're looking at the line your data is actually on.
Tracking a travel eSIM
- Reset the phone's counter when the plan starts (iPhone: Reset Statistics; Android: match the cycle start date). The phone's figure then follows the trip.
- Set a warning below your allowance. For example, set it at 4 GB on a 5 GB plan, so you can top up before data stops.
- Check what the plan has counted. In your Wanderly account, the Data Usage page shows what each eSIM has used, for plans that report usage. Updates can take a few minutes to appear.
- Keep your home line off data. Set the travel eSIM as your data line and turn off data roaming on your home SIM. Otherwise your home carrier's roaming charges can add up alongside the eSIM.
Which apps use the most
Video and video calls use the most data by far; messaging and maps use the least. For real per-hour figures, see:
- How much data YouTube uses
- Does FaceTime use data?
- Does WhatsApp use data?
- How much data Google Maps uses
To size a plan before you go, use the travel data calculator or read how much data you need for travel.
FAQ
How do I check my data usage on iPhone? Go to Settings → Cellular (or Mobile Data). The total for the current period is near the top, and each app's usage is listed below.
How do I check my data usage on Android? On a Pixel, go to Settings → Network & internet → SIMs. On Samsung, go to Settings → Connections → Data usage → Mobile data usage. Other brands use similar menus.
How do I see which app is using the most data? On iPhone, it's the app list in Settings → Cellular. On Pixel, tap App data usage; on Samsung, open Mobile data usage.
Does resetting statistics on iPhone affect my plan? No. It only resets the phone's own counter. Your plan's allowance is tracked by your carrier or eSIM provider.
Why is my phone's data figure different from my carrier's? The two count from different dates and measure in their own ways. Your carrier's or eSIM provider's figure is the official one.
Can I stop my phone from going over my data? On Android you can set a data limit that turns mobile data off at a set amount. On iPhone, turn off data for heavy apps and use Low Data Mode, then keep an eye on Settings → Cellular.